The immunoneurological model of epilepsy provides a more clearly defined target than other models for studying mechanisms because of the well-recognized molecular specificity inherent in antigen-antibody reactions. A simple, reproducible immunoneurological model that can be studied using neurochemical criteria is that induced by a single injection of 10 microns of antiserum to gangliosides into the sensorimotor cortex of rats, producing recurrent epileptiform EEG patterns of up to several weeks duration. Antisera against antigenic components of synaptic membranes other that gangliosides may induce changes that have different characteristics: intensity (frequency and amplitude of maximal spiking), time of onset, duration of response. We wish (1) to compare the effects of antisera directed against dfferent synaptic membrane antigens; (2) to determine dose-response curves with pure antibodies to different antigens; (3) to determine the mechanism of action of antiganglioside antibodies by studying their localization, their persistence, and their possible effects on neurochemical processes such as neurotransmitter release and adenylate cyclase activation; (4) to develop an immunoneurological model that shows convulsive activity as well as EEG changes; (5) to examine implications of this model for possible involvemnt of autoimmunity in epileptic phenomena and (6) to determine whether animals whose development was inhibited by antibodies to synaptic membrane antigens show, as adults, alterations in their seizure thresholds.